MEMS Accelerometer Device for Acoustic Antennas

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Solution Overview

Problem

Conventional accelerometers used in acoustic antennas are costly and physically large, making them unsuitable for dense configurations like towed linear acoustic antennas, where space is limited and numerous sensors are required to measure 3-axis acceleration effectively.

Innovation Solution

A compact accelerometer device utilizing a set of MEMS-type accelerometer sensors arranged in a head-opposite configuration on printed circuit boards, allowing for the determination of acceleration along three axes (X, Y, Z) and enabling the stacking of multiple boards within a single acoustic module, with a processing unit to calculate acceleration references from sensor pairs, accounting for gain and offset calibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional accelerometers are used in acoustic antennas, then acceleration measurement capability is provided, but cost and device size increase significantly

Engineering Contradiction:
Improveacceleration measurement capabilityVSAvoidcost and size
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The conventional single accelerometer unit is segmented into multiple independent MEMS accelerometer sensors (at least three sensors). Each sensor measures acceleration along specific axes, and their outputs are combined through a processing unit to achieve complete 3-axis acceleration measurement. This segmentation allows using smaller, cheaper MEMS sensors instead of a single large conventional accelerometer.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple MEMS accelerometer sensors are merged into a single accelerometer device that functions as a complete 3-axis acceleration measurement system. The processing unit combines the outputs of individual sensors to calculate acceleration references along X, Y, and Z axes, achieving the functionality of a conventional accelerometer while using smaller components.

Inventive Principle:
Principle #5Merging (Combining)

2Measurement precision

If multiple accelerometers are arranged along a long antenna for interpolation, then measurement coverage is improved, but cost increases due to the large number of accelerometers required

Engineering Contradiction:
Improveacceleration measurement coverageVSAvoidnumber of accelerometers
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The accelerometer device with multiple MEMS sensors arranged in specific configurations (e.g., tetrahedral arrangement) can serve multiple measurement purposes simultaneously. The same device provides acceleration references for compensating differential effects on acoustic sensors and can be used for various antenna configurations, reducing the need for multiple specialized accelerometers along the antenna length.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If printed circuit boards are stacked in acoustic modules for redundancy, then operational continuity is ensured, but space constraints prevent integration of conventional accelerometers

Engineering Contradiction:
Improveoperational continuityVSAvoidspace for accelerometer integration
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The accelerometer sensors are arranged in a three-dimensional configuration (such as a tetrahedral arrangement with sensors at vertices) within the limited space of the acoustic module. This spatial arrangement allows multiple sensors to be integrated in the available volume without requiring additional stacking space, enabling the accelerometer device to fit within the constrained environment while maintaining redundancy and reliability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution reduces the overall cost and size of the accelerometer system, enabling reliable 3-axis acceleration measurement while compensating for pressure effects, improving redundancy and reducing error rates, making it suitable for large-scale acoustic antenna applications.

Implementation Method 1

The accelerometer sensors are mounted on at least one of the printed circuit boards, the accelerometer sensors comprising at least three accelerometer sensors mounted on either side of the at least one printed circuit board

Methodology Applied
Scientific EffectInertia: Inertia

Data Source

PatentEP3170007B1Accelerometer device
Publication Date: 2020.05.20 THALES SA
  • EP3170007B1 patent drawingFigure 1~2
  • EP3170007B1 patent drawingFigure 3
  • EP3170007B1 patent drawingFigure 4

AI summary

The invention relates to an accelerometer device for determining the acceleration of an object to which the accelerometer device is mechanically connected, along 3 axes X, Y and Z of a main orthonormal reference system comprising three axes X, Y and Z. Said object is subjected to a surrounding pressure and comprises a number N of MEMS-type accelerometer sensors, said number N being at least equal to two. Each sensor is defined in an auxiliary reference system comprising 3 orthonormal axes. Said group of accelerometer sensors comprises at least one pair of sensors mounted such that the heads are opposing, the sensors being substantially parallel to each other.